The present invention relates to a central communication unit of a motor vehicle. In particular, the present invention relates to a central communication unit of a motor vehicle having a number of connection modules for establishing a wireless data connection between the motor vehicle and at least one transmitting/receiving device located outside of the motor vehicle.
In the case of conventional motor vehicles, the communication between so-called on-board components in the motor vehicle with communication partners outside of the motor vehicle is implemented by means of a communication unit TCB (Telematic Communication Box). In the meantime, motor vehicles contain a multiplicity of devices or on-board components which, when used, need a data link such as, for example, an Internet radio, navigation system with Internet connection, information systems for loading messages etc., and rescue systems which, in the case of an accident, automatically transmit an emergency call. Each on-board component requires a separate communication unit. This results in considerable production costs and the number of communication units is limited due to the limited installation space in a motor vehicle so that it is not possible to provide an arbitrary number of communication units and not possible to provide an arbitrary number of on-board components with a radio link.
For this reason, a central communication unit ATM (Advanced Telecommunication Module) was developed. This central communication unit has a number of connection modules which can establish in each case a radio link according to a particular radio standard. This includes, for example, cellular systems (3G, 4G) and also local, radio-based networks (IEEE 802.11, IEEE 802.16). By this means, the central communication unit can establish a radio link with different standards and, if necessary, even setup a number of radio links on different radio channels in parallel. By means of the central communication module, a data link can thus be established and maintained even if different types of radio networks are available at different positions of the motor vehicle during a trip, the data link being maintained simultaneously or successively via different radio channels with different radio standards. By this means, the optimum radio channel between the motor vehicle and a communication partner located outside the motor vehicle can be selected automatically. The central communication module distributes the existing data rate of the radio links or of the radio channels, respectively, to the individual on-board components.
In the case of simple central communication units, only a single application executed on an on-board component can in each case access the data link between the central communication unit and the external communication partner. There are also central communication units in which a number of applications can communicate virtually simultaneously via the central communication unit. In this case, the data are forwarded without using a prioritization mechanism, for example according to the FIFO principle (First-In First-Out), this being applied to data packets, messages and/or to the entire data link of the respective application.
In the case of the conventional solution comprising a number of separate communication units, all on-board components, to which one communication unit is allocated in each case, can obtain a radio link separately. However, the production and data transmission costs for a multiplicity of communication units are considerable. The number of communication units is limited by the limited installation space. In addition, the multiplicity of communication units will be designed to be relatively simple so that each communication unit can establish at least one radio link or a link via a radio channel according to a particular radio standard (e.g. WLAN, GSM, 3G/UMTS, 4G/LTE).
In the case of the evolving solution by means of a central communication unit, the advantage is that the radio link is switched automatically to the best and/or most advantageous available radio network so that an optimum data link exists. If, however, a number of applications wish to use a data link simultaneously, the problem exists that the individual applications can block each other. In particular, applications which wish to transmit a large volume of data can impair applications which only wish to transmit a small volume of data to such an extent that the applications with a small volume of data are virtually inoperative. This is particularly critical when the applications with a small volume of data are applications which are important to the vehicle driver such as, for example, the transmission of traffic messages or the transmission of an emergency call. If these are impaired by downloading music or a film, this is of considerable disadvantage to the vehicle driver.
The invention is based on the object, therefore, to extend a central communication unit of a motor vehicle in such a manner that a number of applications can communicate efficiently and reliably simultaneously with external communication partners via one or more radio channels.
This and other objects are achieved in accordance with the embodiments of the invention.
An inventive central communication unit of a motor vehicle comprises
a number of connection modules for establishing a wireless data link between the motor vehicle and at least one transmitting/receiving device located outside the motor vehicle, and
a connection module manager for controlling the connection modules in order to provide a suitable data link between the motor vehicle and the at least one transmitting/receiving device,
a data network for connecting a number of devices within the motor vehicle, wherein a number of applications, which can be executed on the devices, can in each case utilize a data link via the central communication unit to the transmitting/receiving device.
The central communication unit is characterized by a communication organization module which is designed in such a manner that the available external connection capacities between the central communication unit and the at least one transmitting/receiving device are distributed actively in accordance with predetermined criteria to the individual active data links of the applications.
The available external connection capacities are the connection capacities of the individual radio channels, the connection capacity of a radio channel basically being the result of the bandwidth or the data rate of the radio channel, respectively. Further parameters such as, e.g., the error rate or the latency can be included in the determination of the connection capacity of the respective radio channel.
A radio channel is a radio link of one or more motor vehicles over a particular frequency of a radio system with a transmitting/receiving device located outside the motor vehicle, i.e. that the connection capacity of the radio channel is distributed to the number of motor vehicles. The distribution is carried out in accordance with the time division multiplex method.
The distribution of the external connection capacities can also be carried out by assigning particular radio channels to particular data links (frequency division multiplex).
It is also possible to perform the distribution of the external connection capacities by means of a combined time- and frequency-division multiplex method.
Due to the provision of the communication organization module it is possible that two or more applications simultaneously in each case use one data link via the central communication unit, wherein the communication organization module distributes or assigns the connection capacities in accordance with the predetermined criteria, especially its requirement for connection capacity and/or a priority of the data links.
In a preferred embodiment, the central communication unit has a connection register in which the data links are registered with their current characteristics or parameters, respectively.
In the connection register, one or more of the following parameters of the data link or of the radio channel, respectively, are stored, in particular, in addition to an identification designator for the data link:                allocation of a radio channel to the respective data link, i.e. entry of an identification designator for the radio channel;        bandwidth allocated to the data link or data rate of the radio channel, respectively, i.e. the amount of data rate occupied by the data link of the total data rate of the respective data channel;        current bandwidth or data rate of the radio channel;        current error rate of the radio channel;        current latency of the radio channel;        data transmission costs of the radio channel.        
With the aid of the connection register, one or more radio channels is or are allocated to a data link by the communication organization module, i.e. one or more physical connections are assigned to a logical connection.
In the connection register, the same radio channels can be allocated to different data links.
Due to the provision of the connection register in the central communication unit, the individual data links are known in the communication organization module so that the individual data links can be monitored selectively by the communication organization module so that the latter can respond to changes in the connection capacities of the radio channels during the data transmission.
Information about the connection capacities is provided via the connection module manager, the latter periodically updating the corresponding information (bandwidth or data rate, error rate, latency, data transmission costs) of the respective radio channel in the connection register.
The central communication unit preferably has an application profile register in which the requirements or parameters of the applications are entered and which, in addition to an identification designator for the application, comprises one or more of the following parameters:                allocation of a data link to the respective application;        current bandwidth or data rate which is available to the application or is granted to it;        application class, the applications being subdivided into a number of classes such as, for example, emergency call (class 1), traffic messages (class 2), VoIP and streaming telephony (class 3) and ftp applications and web pages (class 4);        priority for a data link via a particular radio channel;        minimum data rate with which the application transmits via a data link;        maximum data rate with which the application transmits via a data link;        maximum error rate of the data link;        maximum latency of the data link.        
Due to the provision of the application profile register in the central communication unit, the individual applications which transmit data via in each case a data link are known in the communication organization module so that the data transmissions of the individual applications can be monitored selectively by the communication organization module.
By collating the parameters deposited in the application profile register with the parameters of the connection register, the communication organization module can determine before or during a data transmission whether the available connection capacity of the data link is adequate for the requirements of the respective application and decide during a data transmission whether and how it responds to altered connection capacities.
In motor vehicles, a distinction is made between two different types of applications, static applications which cannot adapt their bandwidth requirements and dynamic applications which can adapt their bandwidth requirements. So that the communication organization module can recognize which type of application (static or dynamic) is present, the application profile register preferably has an entry on the minimum data rate and an entry on the maximum data rate with which an application transmits. In the case of a request for a data link, a static application transmits the same value for both entries or alternatively a single value which is transmitted in both entries whereas a dynamic application conveys two different values which represent the minimum and the maximum data rate of the application and which are entered correspondingly. Using these entries, the communication organization module can thus distinguish between dynamic applications and static applications. By means of this distinction, the communication organization module can adapt its response to a change in the connection capacities to the corresponding options of the respective application.
By means of the communication organization module, it is possible to monitor the quality of service of the data links of the individual dynamic applications and, if necessary, to intervene actively in that more connection capacity is allocated to a particular data link or a dynamic application, respectively, and less connection capacity is allocated to one or more other data links or dynamic applications, respectively.
The communication organization module can intervene in the type of transmission of the data link and inform the respective dynamic application of the maximally achievable or available connection capacity of one or more of the data links and the dynamic application can adapt the application modes based on this information. For example, a dynamic application can change the resolution or the codec during the transmission of video streams or video files in order to match the required connection capacity to the available connection capacity.
A dynamic application can be requested by the communication organization module to increase or to reduce the data capacity up to a complete cancellation of a particular data link.
The communication organization module can cancel a particular data link of a dynamic or static application completely and/or send a request to the corresponding applications to terminate the communication so that they quit their respective data link. The latter can be confirmed by a message of the corresponding application to the communication organization module.
The connection capacity becoming available by a cancellation or by the termination of the communication can be allocated to one or more other data links or applications by the communication organization module.
Alternatively, both registers mentioned can be combined in one register within the central communication unit.
Since there is an m:n relation between the radio channels and the data links, the allocation between the two can also be effected by a further register, e.g. by an allocation register.
The number of connection modules are designed for establishing radio links or connections via radio channels in radio systems according to different standards. These standards are, in particular, WLAN, GSM, GPRS, EDGE, 3G/UMTS, HSPA, 4G/LTE, ETSI ITS-G5. Using the connection modules, radio links having different standards can be operated simultaneously or successively. The radio links are controlled in accordance with predetermined criteria which, in particular, are the availability of the radio channels, the bandwidth, the available data rate, the costs, the latency and the error rate. If the motor vehicle is located in a public WLAN network without access restriction and having a high bandwidth, this WLAN network is preferably used. Since such WLAN networks are localized, the system, after leaving this network, automatically switches to another radio channel which can be designed in accordance with the same or a different standard. This is controlled automatically by the connection module manager so that the optimum radio link exists at any time between motor vehicle and external communication partners.
In a method according to the invention for controlling the communication between a number of applications which are executed on devices, connected to a data network, of a motor vehicle, comprising at least one transmitting/receiving device located outside the motor vehicle, by means of a central communication unit, the number of applications can communicate with the transmitting/receiving device in each case via a data link via the central communication unit, and an available external connection capacity between the central communication unit and the at least one transmitting/receiving device is distributed actively in accordance with predetermined criteria to the individual active data links of the applications by means of a communication organization module.
The communication organization module preferably monitors the data flow of the individual data links from and to the individual applications. Monitoring can take place, for example, by detecting data packets by reading the header of such data packets or by detecting the volume of data which are transmitted via particular ports which are in each case allocated to a data link.
If an application of a device of the motor vehicle wishes a data link to be set up, it sends a corresponding request to the communication organization module with which predetermined parameters of the desired data link are transmitted. These parameters are the parameters entered for the respective data link in the application profile register explained above such as, for example, the identification designator of the application, the class of application, the priority of the data link, the minimum or maximum data rate, the maximum error rate, the maximum latency etc., the minimum data rate being equal to the maximum data rate in the case of static applications.
If the central communication unit has a connection register, the communication organization module can find out with the aid of the parameters entered in the latter whether the available external connection capacities are adequate for the data link of the application, correspondingly respond to the request of the application and provide a data link if these are sufficient for the application. In the latter case, the central communication unit enters in the connection register an identification designator for the data link which it transmits at the same time to the application.
If the central communication unit has an application profile register, the communication organization module enters in it the parameters received from the application during the request for later use.
In this method, a central communication unit is used preferably as it is explained above.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.